In cellular system such as, for example, GERAN, UTRAN or E-UTRAN systems, there can be a number of Application Functions, AFs, for use by User Equipments, UEs, in the system.
The cellular system will also comprise a so called Policy and Charging Rules Function, a PCRF, and a Policy and Charging Enforcement Function, a PCEF.
The PCRF is a functional element which encompasses policy control decision and flow based charging control functionalities. The PCRF provides network control regarding the service data flow detection, gating, QoS and flow based charging, with the exception of credit management, to the PCEF.
The PCRF also provides rules for Policy and Charging Control, PCC, to the PCEF via a reference point known as the Gx reference point, also known as the Gx interface.
Charging a UE for the use of a particular AF is carried out on the basis of a charging identifier, an Access Network Charging Identifier, which is assigned by the system to a dedicated bearer which is used for the services provided by the AF to the UE.